Merge remote-tracking branch 'airlied/drm-fixes' into drm-intel-next-queued

Back-merge from drm-fixes into drm-intel-next to sort out two things:

- interlaced support: -fixes contains a bugfix to correctly clear
  interlaced configuration bits in case the bios sets up an interlaced
  mode and we want to set up the progressive mode (current kernels
  don't support interlaced). The actual feature work to support
  interlaced depends upon (and conflicts with) this bugfix.

- forcewake voodoo to workaround missed IRQ issues: -fixes only enabled
  this for ivybridge, but some recent bug reports indicate that we
  need this on Sandybridge, too. But in a slightly different flavour
  and with other fixes and reworks on top. Additionally there are some
  forcewake cleanup patches heading to -next that would conflict with
  currrent -fixes.

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 273 insertions, 0 deletions

diff --git a/arch/powerpc/mm/icswx.c b/arch/powerpc/mm/icswx.c
new file mode 100644
index 00000000000..5d9a59eaad9
--- /dev/null
+++ b/arch/powerpc/mm/icswx.c
@@ -0,0 +1,273 @@
+/*
+ *  ICSWX and ACOP Management
+ *
+ *  Copyright (C) 2011 Anton Blanchard, IBM Corp. <anton@samba.org>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+#include "icswx.h"
+
+/*
+ * The processor and its L2 cache cause the icswx instruction to
+ * generate a COP_REQ transaction on PowerBus. The transaction has no
+ * address, and the processor does not perform an MMU access to
+ * authenticate the transaction. The command portion of the PowerBus
+ * COP_REQ transaction includes the LPAR_ID (LPID) and the coprocessor
+ * Process ID (PID), which the coprocessor compares to the authorized
+ * LPID and PID held in the coprocessor, to determine if the process
+ * is authorized to generate the transaction.  The data of the COP_REQ
+ * transaction is 128-byte or less in size and is placed in cacheable
+ * memory on a 128-byte cache line boundary.
+ *
+ * The task to use a coprocessor should use use_cop() to mark the use
+ * of the Coprocessor Type (CT) and context switching. On a server
+ * class processor, the PID register is used only for coprocessor
+ * management + * and so a coprocessor PID is allocated before
+ * executing icswx + * instruction. Drop_cop() is used to free the
+ * coprocessor PID.
+ *
+ * Example:
+ * Host Fabric Interface (HFI) is a PowerPC network coprocessor.
+ * Each HFI have multiple windows. Each HFI window serves as a
+ * network device sending to and receiving from HFI network.
+ * HFI immediate send function uses icswx instruction. The immediate
+ * send function allows small (single cache-line) packets be sent
+ * without using the regular HFI send FIFO and doorbell, which are
+ * much slower than immediate send.
+ *
+ * For each task intending to use HFI immediate send, the HFI driver
+ * calls use_cop() to obtain a coprocessor PID for the task.
+ * The HFI driver then allocate a free HFI window and save the
+ * coprocessor PID to the HFI window to allow the task to use the
+ * HFI window.
+ *
+ * The HFI driver repeatedly creates immediate send packets and
+ * issues icswx instruction to send data through the HFI window.
+ * The HFI compares the coprocessor PID in the CPU PID register
+ * to the PID held in the HFI window to determine if the transaction
+ * is allowed.
+ *
+ * When the task to release the HFI window, the HFI driver calls
+ * drop_cop() to release the coprocessor PID.
+ */
+
+void switch_cop(struct mm_struct *next)
+{
+#ifdef CONFIG_ICSWX_PID
+	mtspr(SPRN_PID, next->context.cop_pid);
+#endif
+	mtspr(SPRN_ACOP, next->context.acop);
+}
+
+/**
+ * Start using a coprocessor.
+ * @acop: mask of coprocessor to be used.
+ * @mm: The mm the coprocessor to associate with. Most likely current mm.
+ *
+ * Return a positive PID if successful. Negative errno otherwise.
+ * The returned PID will be fed to the coprocessor to determine if an
+ * icswx transaction is authenticated.
+ */
+int use_cop(unsigned long acop, struct mm_struct *mm)
+{
+	int ret;
+
+	if (!cpu_has_feature(CPU_FTR_ICSWX))
+		return -ENODEV;
+
+	if (!mm || !acop)
+		return -EINVAL;
+
+	/* The page_table_lock ensures mm_users won't change under us */
+	spin_lock(&mm->page_table_lock);
+	spin_lock(mm->context.cop_lockp);
+
+	ret = get_cop_pid(mm);
+	if (ret < 0)
+		goto out;
+
+	/* update acop */
+	mm->context.acop |= acop;
+
+	sync_cop(mm);
+
+	/*
+	 * If this is a threaded process then there might be other threads
+	 * running. We need to send an IPI to force them to pick up any
+	 * change in PID and ACOP.
+	 */
+	if (atomic_read(&mm->mm_users) > 1)
+		smp_call_function(sync_cop, mm, 1);
+
+out:
+	spin_unlock(mm->context.cop_lockp);
+	spin_unlock(&mm->page_table_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(use_cop);
+
+/**
+ * Stop using a coprocessor.
+ * @acop: mask of coprocessor to be stopped.
+ * @mm: The mm the coprocessor associated with.
+ */
+void drop_cop(unsigned long acop, struct mm_struct *mm)
+{
+	int free_pid;
+
+	if (!cpu_has_feature(CPU_FTR_ICSWX))
+		return;
+
+	if (WARN_ON_ONCE(!mm))
+		return;
+
+	/* The page_table_lock ensures mm_users won't change under us */
+	spin_lock(&mm->page_table_lock);
+	spin_lock(mm->context.cop_lockp);
+
+	mm->context.acop &= ~acop;
+
+	free_pid = disable_cop_pid(mm);
+	sync_cop(mm);
+
+	/*
+	 * If this is a threaded process then there might be other threads
+	 * running. We need to send an IPI to force them to pick up any
+	 * change in PID and ACOP.
+	 */
+	if (atomic_read(&mm->mm_users) > 1)
+		smp_call_function(sync_cop, mm, 1);
+
+	if (free_pid != COP_PID_NONE)
+		free_cop_pid(free_pid);
+
+	spin_unlock(mm->context.cop_lockp);
+	spin_unlock(&mm->page_table_lock);
+}
+EXPORT_SYMBOL_GPL(drop_cop);
+
+static int acop_use_cop(int ct)
+{
+	/* todo */
+	return -1;
+}
+
+/*
+ * Get the instruction word at the NIP
+ */
+static u32 acop_get_inst(struct pt_regs *regs)
+{
+	u32 inst;
+	u32 __user *p;
+
+	p = (u32 __user *)regs->nip;
+	if (!access_ok(VERIFY_READ, p, sizeof(*p)))
+		return 0;
+
+	if (__get_user(inst, p))
+		return 0;
+
+	return inst;
+}
+
+/**
+ * @regs: regsiters at time of interrupt
+ * @address: storage address
+ * @error_code: Fault code, usually the DSISR or ESR depending on
+ *		processor type
+ *
+ * Return 0 if we are able to resolve the data storage fault that
+ * results from a CT miss in the ACOP register.
+ */
+int acop_handle_fault(struct pt_regs *regs, unsigned long address,
+		      unsigned long error_code)
+{
+	int ct;
+	u32 inst = 0;
+
+	if (!cpu_has_feature(CPU_FTR_ICSWX)) {
+		pr_info("No coprocessors available");
+		_exception(SIGILL, regs, ILL_ILLOPN, address);
+	}
+
+	if (!user_mode(regs)) {
+		/* this could happen if the HV denies the
+		 * kernel access, for now we just die */
+		die("ICSWX from kernel failed", regs, SIGSEGV);
+	}
+
+	/* Some implementations leave us a hint for the CT */
+	ct = ICSWX_GET_CT_HINT(error_code);
+	if (ct < 0) {
+		/* we have to peek at the instruction word to figure out CT */
+		u32 ccw;
+		u32 rs;
+
+		inst = acop_get_inst(regs);
+		if (inst == 0)
+			return -1;
+
+		rs = (inst >> (31 - 10)) & 0x1f;
+		ccw = regs->gpr[rs];
+		ct = (ccw >> 16) & 0x3f;
+	}
+
+	if (!acop_use_cop(ct))
+		return 0;
+
+	/* at this point the CT is unknown to the system */
+	pr_warn("%s[%d]: Coprocessor %d is unavailable",
+		current->comm, current->pid, ct);
+
+	/* get inst if we don't already have it */
+	if (inst == 0) {
+		inst = acop_get_inst(regs);
+		if (inst == 0)
+			return -1;
+	}
+
+	/* Check if the instruction is the "record form" */
+	if (inst & 1) {
+		/*
+		 * the instruction is "record" form so we can reject
+		 * using CR0
+		 */
+		regs->ccr &= ~(0xful << 28);
+		regs->ccr |= ICSWX_RC_NOT_FOUND << 28;
+
+		/* Move on to the next instruction */
+		regs->nip += 4;
+	} else {
+		/*
+		 * There is no architected mechanism to report a bad
+		 * CT so we could either SIGILL or report nothing.
+		 * Since the non-record version should only bu used
+		 * for "hints" or "don't care" we should probably do
+		 * nothing.  However, I could see how some people
+		 * might want an SIGILL so it here if you want it.
+		 */
+#ifdef CONFIG_PPC_ICSWX_USE_SIGILL
+		_exception(SIGILL, regs, ILL_ILLOPN, address);
+#else
+		regs->nip += 4;
+#endif
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(acop_handle_fault);